This invention relates to a machine and method for continuously forming a series of filled packages or pouches from a continuous strip or web of flexible material. Pouches of this type have long been used to package a wide variety of products such as sugar, sweeteners, drink mixes, soup mixes and the like in individual or small serving sizes. Liquid products as well as dry products can be packaged in this type of pouch. A variety of web materials can be used such as paper or foil which are relatively stiff and non-extensible or oriented polypropylene or polyester which are somewhat soft and extensible. The web may be coated on at least one side with a heat sealable material such as polyethylene which is suitable for forming heat seals.
An example of a prior art pouch machine is shown in U.S. Pat. No. 5,699,653, the disclosure of which is incorporated herein by reference. The typical pouch machine includes a base supporting various components including an unwind stand for supporting a roll of pouch material. The web is unwound in a generally horizontal plane and advanced to a plow which folds the web generally in half about a longitudinal fold line. The fold line is disposed at the bottom of the web which then assumes a generally V-shape with front and back panels on either side of the fold in a substantially vertical plane.
The folded web is then pulled around a rotary vertical sealer which has a series of vertically extending circumferentially spaced heated lands on its periphery which are provided to form longitudinally spaced, vertically extending heat seals in the web. This sealing process forms pockets or pouches between the front and back panels of the web. The tops or mouths of the pouches remain open for filling at a filling wheel which opens the pouches and inserts the desired quantity of the product being packaged. Thereafter, the web is moved to a top sealer which seals the tops. The filled and sealed pouches are transferred to a knife which severs the pouches into individual pouches or groups of pouches.
Sometimes pouch machines have been set up to form pouches or connected groups of pouches having different products in adjacent pouches, e.g., multi-flavor packs of drink mixes. U.S. Pat. No. 5,605,183 shows an example of a filling wheel for filling different products. Recently this multi-product concept has been extended to comestibles having two or more components packaged separately which the user mixes or otherwise prepares at the time of use. These components can be packaged in adjacent, non-separated pouches, as in the case of multi-flavor packs. But in some instances the components may have markedly differing characteristics. For example, macaroni and cheese has a first component which is a powder cheese flavoring mix and a second component which is a somewhat voluminous dry pasta product. In a typical single serving size the volume of the pasta is much greater than that of the appropriate amount of flavoring mix. So while a fairly large pouch volume is required to accommodate the pasta a much smaller volume is sufficient for the flavoring mix. Obviously in this instance if all pouches are of the same size the pouch will be not be the optimum size for one component or the other. If a small pouch appropriate for the flavoring mix is used then multiple pouches will be required for the pasta. This is not the best situation because it complicates the preparation instructions. If a pouch large enough for the pasta is used, the flavoring mix will nowhere near fill it. This latter instance is undesirable because consumers have a tendency to believe they have been sold either a defectively filled package or a miserly amount of flavoring mix when in fact neither is the case.
A solution to this dilemma is to make a small pouch for the flavoring mix and a large pouch for the pasta. The combination of a small and a large pouch will be referred to herein as a package. Thus, a package contains at least two pouches of different widths or pitches which are not separated from one another and contain different products. The package can be described as being multi-pitch and multi-product. The non-separated pouches may be perforated or scored at the adjoining seal to facilitate separation by the ultimate consumer.
Multi-pitch packages have been made in the past on intermittent motion machines. These are machines where the web of pouch materials alternately starts and stops as it makes its way through the various stations. In other words a particular pouch advances to a station, stops, has an operation performed on it while stationary at that station, then moves to the next station where the next operation is performed while stationary, and so on. On an eight and a half inch package width, intermittent machines might be able to produce 100 packages per minute. The present invention provides a continuous pouch making machine having a five-fold increase in production of multi-pitch, multi-product packages.
One of the problems with high speed continuous pouch packaging machines is the need to open the pouches for filling. It will be appreciated that after folding and formation of the side seals, the web is essentially a flat, two-dimensional structure which must be expanded into a three-dimensional form for the pouch to accept the product therein. The above-referenced U.S. Pat. No. 5,699,653 provides an air curtain that inflates the pouches with compressed air. The present invention provides an enhancement to the air curtain of the 5,699,653 patent that is particularly advantageous with multi-pitch, multi-product packages.